Don't bring in llvm/Support/thread.h in Threading.cpp
Doing so defines the type llvm::thread. On FreeBSD, we need
to call a macro which references its own ::thread type, which
causes an ambiguity due to ADL when inside of the llvm namespace.
Since we don't even need this unless LLVM_ENABLE_THREADS == 1,
we don't even need this type anyway, as it is always equal to
std::thread, so we can just use that directly.
llvm-svn: 296891
diff --git a/llvm/lib/Support/Threading.cpp b/llvm/lib/Support/Threading.cpp
index a9ecf9b..2feb16e 100644
--- a/llvm/lib/Support/Threading.cpp
+++ b/llvm/lib/Support/Threading.cpp
@@ -15,7 +15,6 @@
#include "llvm/Support/Threading.h"
#include "llvm/Config/config.h"
#include "llvm/Support/Host.h"
-#include "llvm/Support/thread.h"
#include <cassert>
#include <errno.h>
@@ -56,10 +55,17 @@
#else
+#include <thread>
unsigned llvm::heavyweight_hardware_concurrency() {
+ // Since we can't get here unless LLVM_ENABLE_THREADS == 1, it is safe to use
+ // `std::thread` directly instead of `llvm::thread` (and indeed, doing so
+ // allows us to not define `thread` in the llvm namespace, which conflicts
+ // with some platforms such as FreeBSD whose headers also define a struct
+ // called `thread` in the global namespace which can cause ambiguity due to
+ // ADL.
int NumPhysical = sys::getHostNumPhysicalCores();
if (NumPhysical == -1)
- return thread::hardware_concurrency();
+ return std::thread::hardware_concurrency();
return NumPhysical;
}